The study is concerned with cyclic AMP--dependent protein kinase from salivary glands (principally the pig parotid gland) and a delineation of substrates of protein kinase in the gland. These include plasma membranes and secretory (zymogen) granule membranes. A soluble protein kinase has been isolated from the pig parotid gland and will be investigated as to its interaction with the membranes of interest. Phosphorylation of the membranes in the presence of protein kinase will be tested and studied kinetically. A detailed characterization of phosphorylation products in these preparations will be pursued. Characterization will include polyacrylamide gel electrophoresis. Interaction of purified protein components of the membranes with protein kinase will also be investigated. An assessment of the presence and role of any membrane-bound protein kinase in the parotid gland will be made as well as a comparison of its characteristics with those of the soluble protein kinase. The study involves an evaluation of possible functional effects of protein kinase on membrane fractions from the parotid gland. This includes effects of protein kinase on calcium binding and uptake by the membranes. Finally, a determination of any protein kinase substrates in saliva will be made and their relation to th secretory event investigated. BIBLIOGRAPHIC REFERENCES: Dowd, F.J., Pitts, B.J.R., and Schwartz, A., Phosphorylation of a low molecular weight polypetide in beef heart Na ion, K ion-ATPase preparations. Arch. Biochem. Biophys. 175: 321-331, 1976. Dowd, F.J. and Shannon, I.L., Kinetic properties of a cyclic AMP-dependent protein kinase from pig parotid gland. Archs. oral Biol. 21:423-429, 1976.